Scientists use effort to treat soil in Africa

University of Hawaii-Manoa soil scientists have improved food production and increased drinking water in drought regions of West Africa by capturing rainfall that normally runs off.

They are adding organic matter to improve soil quality and looking at charcoal as an alternative, both to increase soil fertility and replace toxic wood burning, said Goro Uehara, soil scientist with the Tropical Plant and Soil Science Department.

He said a U.S. Agency for International Development medical official asked the UH team to convert biomass to charcoal as a fuel because wood-burning is a major health issue on a global scale.

"There is a great movement of trying to encourage people to go from wood burning to charcoal burning," Uehara said. But commercial charcoal, while better than wood, contains carbon monoxide, he said.

Uehara envisions increased factory production globally with charcoal made from green waste in a flash carbonization method developed by professor Michael Antal Jr. in the Hawaii Natural Energy Institute.

Uehara and UH soil scientists Russell Yost and Richard Kablan are engaged in a USAID Soil Management Collaborative Support Project in West Africa. Uehara is director of the soil management entity, and Yost is principal investigator.

"We're looking for win-win situations where we can remove carbon from the atmosphere and put it in soil where it has multiple benefits," Yost said.

Almost half of West Africa is in what is called a no-vegetation zone because it is so dry, resulting in famine and other catastrophes, Yost said.

In Mali the scientists are installing ridges of hard soil to capture rain. "The zone has quite a lot of rainfall, but it's sort of an agronomic drought because 61 percent runs off," Yost said. With use of the ridges, only 22 percent runs off, he said.

"By capturing water you're reducing erosion, which really accelerates carbon loss," he pointed out. "With this technology, water and soil stay in place, and as a result, carbon levels increase."

Carbon also is increased in lower levels of the soil that trees can use, Uehara said, referring to a photo of spontaneous baobab tree growth.

"It is very exciting," Kablan said. "It makes a big difference in a small country. We saw the transformation just before our eyes in a village with no water that couldn't grow anything. They're growing corn now."

The UH team and partner institutions extended the technology to Senegal, Gambia and other countries.